I. Field of the Invention
The present invention relates to a vent cap.
II. Description of the Prior Art
There have been a number of previously known vent caps which are attached to and close an opening, such as the fill port for an oil reservoir, on a particular machine or device. Such vent caps typically include an air filter to remove any impurities from air entering into or exhausting from the machine opening. The previously known vent caps, however, have suffered from a number of different disadvantages.
One disadvantage of the previously known vent caps is that such caps are complex in construction and, therefore, expensive to manufacture. Furthermore, the cost of the vent cap is very important since, once the filter has become clogged with impurities, the vent cap must be replaced.
A still further disadvantage of many of the previously known vent caps is that the air filter employed within the vent cap have had a relatively small surface area. Because of the relatively small surface area of the filter used in the previously known vent caps, the air filter becomes rapidly clogged and requires replacement.
A still further disadvantage of many of the previously known vent caps is that such vent caps use only a bolt and nut arrangement to secure a dip stick, when desired, to the vent cap. After long usage, particularly in hostile operating environments, the bolt and nut tend to loosen causing the bolt or nut as well as the dip stick to fall downwardly through the opening and into the machine. Such small objects, furthermore, can cause great damage to the machine.